Fluid powered centrifugal separators are well-known for separating fluids of different densities or for separating particulate matter from liquids and have long been used in lubrication systems for engines, particularly diesel powered vehicle engines (automobiles and ships), as well as in other industrial separation processes. The principle of operation of such a separator is that a housing contains a rotor which is supported therein to spin at high speed about a substantially vertical axis provided by a central tube. Fluid is supplied at elevated pressure along the axis of rotation and is ejected from tangentially directed nozzles in the base of the rotor into the housing from which it drains to a sump. In self-powered separators the drive fluid for the rotor is the contaminated fluid which is to be cleaned. As this fluid passes through the rotor, denser contaminant materials or particles are separated there from centrifugally and retained in the rotor, typically as a cake adhering to the interior surface of the rotor.
The rotor interior is typically divided, by means of a separation cone, into two separate, but communicating chambers, namely an upper chamber which receives the incoming fluid and the contaminant particles, and a lower chamber from which the fluid emerges via the nozzles. The separation cone provides a frusto-conical wall which inclines downwards from an upper rim in the vicinity of the central tube to a lower periphery adjacent the interior surface of the rotor. An opening is provided for passage of fluid from the upper to the lower chamber by either a gap between the inner rim of the separation cone and the central tube or, where the inner rim is mounted as a closed fit around said tube, by one or more apertures in the separation cone in the vicinity of the central tube. Fluid enters the upper chamber of the rotor through apertures in the central tube, flows firstly down the interior surface of the rotor upper chamber and then up the surface of the separation cone before passing into the lower chamber through aforesaid opening, and thence to exit via the nozzles. The separation cone is important in preventing detritus, namely contaminant particles, from falling directly into the area of the nozzles, thus minimizing risk of any blockage. It also causes a change of direction of oil flow inwardly towards the central support tube before it can pass into the lower chamber. This slows the flow and allows more time for the contaminant particles to be trapped on the inner surface of the rotor upper chamber, thus increasing separation/cleaning efficiency of the rotor.
The rotor itself is typically formed in two parts as an upper bell shaped cover and a lower base. In older arrangements, for example as disclosed in GB 2283694, these were connected together by crimping and the periphery of the separation cone was connected there between in the crimping operation. In more recent commercial versions of centrifugal separator the cover is typically threaded connected to the base and can therefore be unscrewed and screwed on again in servicing operations. In this respect, contaminant debris deposited in the interior of the upper chamber, most adhering to the interior wall, but some not well adhered or lying free within the chamber, needs to be periodically removed. This may be done, for example, once or twice a year during vehicle servicing in the case of centrifugal separators in automotive vehicles, or may be done much more frequently in other industrial uses of centrifugal separators of this self driven type.
The separation cone may be mounted by its upper rim fitting onto the central tube or by friction fit inside the rotor. When the cover is separated from the base of the rotor for servicing purposes, namely cleaning out of the separator, the separation cone may stay with the cover or it may stay with the base. There is no consistency, and no possibility of a predetermined sequence of servicing operations. There is always a servicing operation, cleaning out the cover interior. Also, there is a possibility that the risk that the separation cone will not stay with the cover when the cover is removed and that debris will drop out of the cover, either into the base which could be detrimental in later blocking a nozzle, or nearby, causing mess and contamination and delay in what is already a dirty and messy part of the separation cone will be glued by dirt to the interior of the cover, making one or both difficult to remove in disassembly of the rotor, and again risking spillage and contamination of the servicing area. If a tool has to be used in order to separate the cone, there is additionally the risk of damage to the parts which may prevent reassembly to a fully efficient rotor condition. In this respect, it is most important that particulate matter debris is not allowed to pass into the base, namely that there is no gap allowing this between the periphery of the separation cone and the interior surface of the rotor. It is equally important that the symmetrical balance of the rotor is maintained upon reassembly following servicing in order to retain efficient centrifugal separation and maintain the effective life of the rotor, namely minimize vibration and wear which can occur through imbalance in operational conditions.
It is therefore an objective of the present invention is to disclose a centrifugal separator that avoids the above-mentioned problems of existing centrifugal separator design.